As cricket's T20 domestic champions battle it out for supremacy in South Africa, alarm bells are ringing that the proliferation of such tournaments has "considerably increased the risk" of match-fixing.

Less than a decade after the 20-over game made its debut in England, every major cricketing country now has its own T20 tournament: attracting new fans and lucrative sponsorship deals -- and the attention of illegal betting syndicates.

An Indian TV sting last week, in which six South Asian umpires were shown to be allegedly open to bribery, was just the latest in a line of scandals to have hit the sport, especially T20 cricket.

A recent review commissioned by the International Cricket Council (ICC) into its anti-corruption activities was unequivocal in pinpointing where the greatest threat to cricket's integrity lies.

"The view of those consulted is that the arrival of T20 cricket and the Indian Premier League has considerably increased the risk of match-fixing and spot-fixing," said the review led by former Hong Kong solicitor-general Bertrand de Speville.

The best known tournament is the Indian Premier League (IPL), a six-week jamboree infused with the glamour of Bollywood stars as well as the biggest names in world cricket.

But as the leagues spread across the cricketing world -- from Bangladesh to Zimbabwe -- experts say the dangers should be clear to all.

"The mushrooming of domestic T20 leagues brings in not merely sponsors, spectators and TV revenue, but also a surging interest from the betting mafia," writer Sharda Ugra argued in a recent commentary for the Cricinfo website.

"They will not stop trying to find new footholds in the game. Protecting cricket's integrity does not only involve reacting to TV stings every few months. It is now a 24x7 undertaking."

The cash-rich IPL initially snubbed an offer by the ICC's anti-corruption unit to monitor matches for the first two editions in 2008 and 2009.

But in a bid to quash speculation that it was a haven for match-fixers, it decided to enlist the unit from the third year onwards.

Five Indian cricketers were suspended during this year's IPL after a sting by the same India TV channel claimed to unearth evidence that no-balls could be arranged to order.

Other tournaments have also been tainted by scandal.

Bangladesh banned former international Shariful Haque indefinitely in September after he was found to have approached current star Mashrafe Mortaza for spot-fixing during its T20 tournament.

During the Sri Lanka Premier League in August, the country's cricket chiefs were alerted to a possible match-fixing attempt by one of the team owners.

Sri Lanka Cricket announced an investigation at that time, but has remained silent on its progress.

Meanwhile, players and administrators of the Indian Cricket League, the ill-fated rival to the IPL, traded accusations of match-fixing after the tournament's demise in 2009.

The ICC established its anti-corruption unit (ACSU) under former London Metropolitan police chief Paul Condon after South African skipper Hansie Cronje's was banned for life over a match-fixing scandal in 2000.

And according to de Speville, the risk of corruption in cricket is not "any less today" than when Condon and his team began work.

The ongoing Champions League T20 in South Africa is not only policed by the ICC's anti-corruption unit but also officiated by its elite panel of umpires.

But not all boards work with the ICC's monitors.

Bangladesh for example posted their own security officials at their event as well as hiring their own umpires.

The Bangladesh Cricket Board insists that its own measures are adequate.